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Untethered electrical stimulation or pacing of the heart is of critical importance in addressing the pressing needs of cardiovascular diseases in both clinical therapies and fundamental studies. Among various stimulation methods, light illumination-induced electrical stimulation via photoelectric effect without any genetic modifications to beating cells/tissues or whole heart has profound benefits. However, a critical bottleneck lies in the lack of a suitable material with tissue-like mechanical softness and deformability and sufficient optoelectronic performances toward effective stimulation. Here, we introduce an ultrathin (<500 nm), stretchy, and self-adhesive rubbery bio-optoelectronic stimulator (RBOES) in a bilayer construct of a rubbery semiconducting nanofilm and a transparent, stretchable gold nanomesh conductor. The RBOES could maintain its optoelectronic performance when it was stretched by 20%. The RBOES was validated to effectively accelerate the beating of the human induced pluripotent stem cell-derived cardiomyocytes. Furthermore, acceleration of ex vivo perfused rat hearts by optoelectronic stimulation with the self-adhered RBOES was achieved with repetitive pulsed light illumination. [ABSTRACT FROM AUTHOR]

Electrical stimulation of existing three-dimensional bioprinted tissues to alter tissue activities is typically associated with wired delivery, invasive electrode placement, and potential cell damage, minimizing its efficacy in cardiac modulation. Here, we report an optoelectronically active scaffold based on printed gelatin methacryloyl embedded with micro-solar cells, seeded with cardiomyocytes to form light-stimulable tissues. This enables untethered, noninvasive, and damage-free optoelectronic stimulation-induced modulation of cardiac beating behaviors without needing wires or genetic modifications to the tissue solely with light. Pulsed light stimulation of human cardiomyocytes showed that the optoelectronically active scaffold could increase their beating rates (>40%), maintain high cell viability under light stimulation (>96%), and negligibly affect the electrocardiogram morphology. The seeded scaffolds, termed optoelectronically active tissues, were able to successfully accelerate heart beating in vivo in rats. Our work demonstrates a viable wireless, printable, and optically controllable tissue, suggesting a transformative step in future therapy of electrically active tissues/organs.

Wireless communication technologies for bioelectronic implants enable remote monitoring for diagnosis and adaptive therapeutic intervention without the constraints of wired connections. However, wireless data uplink from millimeter-scale devices deep in the body struggles to achieve low power consumption while maintaining large misalignment tolerances. Here, we report a passive wireless backscatter communication system based on magnetoelectric transducers that consumes less than 0.3 pJ/bit and achieves less than 1E-6 bit error rate at a distance of 55 mm while tolerating a misalignment of 10 mm. Using this robust data uplink, we designed a wireless cardiac sensing node that can transmit electrocardiogram signals from the beating heart surface of a porcine model to a custom external transceiver using the magnetoelectric backscatter uplink. This reliable, near-zero-power communication method provides opportunities for next-generation bioelectronics to feature real-time physiological monitoring and closed-loop therapies while maintaining a small form factor and low power consumption., Competing Interests: Conflict of interest F.A., J.E.W., K.Y., and J.T.R. receive monetary and/or equity compensation from Motif Neurotech. The terms of these arrangements have been reviewed and approved by Rice University in accordance with their policies on conflict of interest in research.

Networks of miniature bioelectronic implants would enable precise measurement and manipulation of the complex and distributed physiological systems in the body. For example, sensing and stimulation nodes throughout the heart, brain, or peripheral nervous system would more accurately track and treat disease or support prosthetic technologies with many degrees of freedom. A main challenge to creating this type of in-body bioelectronic network is the fact that wireless power and data transfer are often inefficient when communicating through biological tissues. This challenge is typically compounded as one increases the number of implants within the network. Here, we show that magnetoelectric wireless data and power transfer enable a network of millimeter-sized bioelectronic implants where the power transfer efficiency of the system improves as the number of implanted devices increases. Using this property, we demonstrate networks of wireless battery-free bioelectronics ranging from 1 to 6 implants where the wireless power transfer efficiency for the system increases from 0.2% to 1.3%, with each node in the network receiving 2.2 mW at a distance of 1 cm. We use this system for efficient and robust wireless data and power transfer to demonstrate proof-of-concept networks of miniature spinal cord stimulators and cardiac pacing devices in large animals. The scalability of this network architecture enabled by magnetoelectric wireless power transfer provides a platform for building wireless closed-loop networks of bioelectronic implants for next-generation electronic medicine., Competing Interests: Competing interests J.T.R., F.A., and J.E.W. receive monetary and/or equity compensation from Motif Neurotech. A.F. is a consultant for Medtronic, Inc. and Abbott, Inc. M.R. receives monetary and/or equity compensation from Maxwell Biomedical, Rhythio, XNHealth, consults for Ziopatch, and is the medical director for IRhythm. The terms of these arrangements have been reviewed and approved by Rice University, the Houston Methodist Research Institute, Baylor College of Medicine, and The Texas Heart Institute in accordance with their policies on conflict of interest in research. The other authors declare no competing interests.

Objectives: Previous studies show that the distal transradial approach (dTRA) is safe and effective for coronary angiography and percutaneous coronary intervention. However, the effect of dTRA on radiation exposure in the catheterization laboratory has not been characterized. The authors analyzed the available literature to compare the radiation exposure associated with dTRA vs the traditional radial approach (TRA)., Methods: A systematic review and meta-analysis of the scientific literature was conducted by using relevant terms to search the PubMed, Embase, and Cochrane Library databases from their inception until October 13, 2022, to identify randomized controlled trials (RCTs) comparing dTRA with TRA. The primary outcome was radiation exposure reported as fluoroscopy time, air kerma, or kerma-dose product. The standard mean difference (SMD) and its 95% confidence interval were used to summarize continuous variables. Random effect and meta-regression also were used for analyses., Results: Among 484 studies identified, 7 were RCTs, with a total of 3427 patients (1712 dTRA, 1715 TRA). No difference was found between dTRA and TRA in radiation exposure quantified as fluoroscopy time (SMD -0.10 [-0.36, 0.15], P=.43) or air kerma (SMD -0.31 [-0.74, 0.13], P=.17). The overall estimate favored lower kerma-area product in the TRA (SMD 0.19 [0.08, 0.30], P=.0006). Meta-regression showed no correlation between fluoroscopy time and year of publication., Conclusions: Compared with TRA, dTRA was associated with significantly greater radiation exposure per the kerma-area product during interventional cardiology procedures, with no differences in fluoroscopy time and air kerma.